That's not consistent with my experience using the Ready indicator. The only thing that removes the Ready indicator for me is a change in Schedule State or in my custom Kanban state when moving an item between states on my Kanban board or another board view, which is exactly the way that the Ready indicator is supposed to behave. Editing other properties of a story has no impact on the Ready indicator in any of my tests.
If you're seeing something different from that then you might consider opening a case with CA Support. Hope that helps.